Incorporation of one or more seats, particularly in open boats designed for fishing and relaxation purposes, is well known. One well known technique for removably securing a seat to a boat deck is to provide a seat mounting rail on the boat and a mounting plate on the bottom of the seat having complementary connectors. Seat mounting rails may be located in more than one position in the boat and the complementary connectors may be such that more than one seat can be secured to a single rail. In addition to the seats mounted on the rail, one or more additional seats may be mounted on a swivel type of pedestal base to support a fisherman in an elevated position. Regardless of the configuration, heretofore it has been necessary to provide a plurality of independent seat assemblies, designed either for attachment to the seat mounting rail or the pedestal base, but not adapted for movement between both positions. Such an arrangement is obviously inefficient and costly.